/Engine/Source/Runtime/Engine/Classes/Animation/AnimData/IAnimationDataController.h
Adds a new bone animation track for the provided name. Broadcasts a EAnimDataModelNotifyType::TrackAdded notify if successful.
The index at which the bone track was added, INDEX_NONE if adding it failed
virtual int32 AddBoneTrack ( [FName](API\Runtime\Core\UObject\FName) BoneName, bool bShouldTransact )